A plug cap electrically connects a spark plug, which is mounted on an internal combustion engine, to a plug cord, which extends from an ignition coil or a distributor, in order to apply a high voltage to the spark plug. As the plug cap, there is known a plug cap including a terminal body which is made of a resin and of which at least both end portions have a cylindrical shape and a cylindrical rubber member that is mounted on an end portion of the terminal body. The rubber member includes a cylindrical inner cylindrical portion, a cylindrical outer cylindrical portion that is disposed close to the outer periphery of the inner cylindrical portion with a predetermined gap interposed therebetween, and a connecting portion that connects the inner cylindrical portion to the outer cylindrical portion. An end portion of the terminal body is fitted between the inner and outer cylindrical portions, so that the rubber member is mounted. In addition, when the plug cap is connected to the spark plug or the plug cord, the spark plug or the like is inserted into the rubber member, so that a gap between the spark plug or the like and the rubber member is sealed (for example, see Patent Document 1 or the like).
Meanwhile, as the terminal body, there is a terminal body that includes concave and convex portions formed on the outer peripheral surface thereof. Further, as the terminal body, there is not only a straight terminal body but also a terminal body that is bent at a predetermined position, in order to cope with a state where the spark plug is assembled on an internal combustion engine. Accordingly, when the above-mentioned terminal body is formed, it is not possible to mold the outer portion of the terminal body by only one mold. Accordingly, the terminal body is generally formed by the molding using a plurality of split molds. For example, as shown in FIGS. 9A and 9B, pins 91 and 92, which are used to define the inner peripheral portion of the terminal body, and split molds 93 and 94, which include molding surfaces corresponding to the outer shape of the terminal body, are disposed at predetermined positions. Then, the split molds are closed. Then, after a cavity (space), which is formed by the pins 91 and 92 and the split molds 93 and 94, is filled with a plasticized resin, the resin is solidified. After that, the split molds 93 and 94 are opened and the pins 91 and 92 are taken out, so that the terminal body is formed.